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Soda Ash Wash And Electric Firing

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Babs    386

Thinking of applying a soda wash to the bottom third of pots. I know somewhere there was much discussion about this but cannot find the posts.

I like the effects I've seen but realise these were done in reduction firing.

I'm looking for a sheen effect.

a. what effects have been realised by this in oxidation?

b. Does any colouring come from the wash or will the bisque ware which has had iron applied and wiped off get enhanced by this process in oxidation?

c. What detrimental effects on elements?

I am using a fairly bland white body.

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bciskepottery    925

You can vary the effect by the ratio of soda ash to water (hot). I think Chris C. used 1/4c soda ash to a cup of water; I've been going with less -- more like 1/8c soda ash to a cup of water. Basically, you get a sheen on the bare clay surface. Works for me as I do a lot of oxide washes on bare clay for exteriors and the slight sheen gives it a bit of finished look, vs. just fired clay.

 

Application will make a difference. You need to be fairly consistent in applying the soda ash wash. Too much/too heavy will make a spot shinier than others. I usually just dip a small sponge in the solution, wring it out, then wipe. I'd rather do a couple of light solution passes than one heavy one.

 

I apply oxides/stains/underglazes to greenware at leatherhard so it gets bisqued; that reduces bleeding, etc. from the soda ash was applied for the glaze firing. But, you may get some bleeding. Just have to practice and experiment with application process).

 

I only do a small number of pieces per load; that is not enough soda to really impact elements. Just run a bisque between glaze loads and your burn off any residual stuff from the elements.

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JBaymore    1,432

If you start doing whole loads of this on the pieces... expect decreased element life.  But that is the "cost of doing business" to get the effect if you like it.  Will the result let you charge a bunch more for your work?  If so... just do it and replace elements more often.

 

A single piece here and there ... if kept from being right up against the area of the element... is not going to be detrimental.

 

Any soda bearing glazes that tyou are firing in the kiln are already outgassing soda into the atmosphere.  SO a whole load of soad feldspar glazed wares is doing as much as a single piece or two with this treatment.

 

best,

 

..................john

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JBaymore    1,432

Should I assume that ash type glazes would also cause faster element degradation, John?

 

Yeah......  potassium and sodium both tend to be a bit fugitive.  But we are talking a small percentage change in life here.

 

best,

 

..................john

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Patat    10

If you're worried about element life, you can put these pots inside a saggar. you can also then place small cups of solid soda ash around in the saggar for a fuming effect.

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oldlady    1,323

any photos of what you are trying to achieve?  i just discovered a bag of soda ash on the shelf and cannot remember why i bought it.  maybe to make more magic water.

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flowerdry    128

Thanks Bruce.  I'm going to try it on a brown cone 10 clay.  I'll let you all know how it comes out.  Interesting thought about the saggar.

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Babs    386

any photos of what you are trying to achieve?  i just discovered a bag of soda ash on the shelf and cannot remember why i bought it.  maybe to make more magic water.

Old Lady my original post was in 2014..

The soda wash, which I applied to bisque ware gave a satin subtle surface to t he unglazed clay area. I made a few yunomi for an exhibiton and wanted the unglazed area, about the bottom 1/3 to have this effect. It worked.

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Roberta12    135

That is funny this thread popped up again.  I saw the soda ash wash picture in John Britt's book and thought it would be fun to try.  I got some soda ash from a tie dying friend. I had a heck of a time getting the soda ash to dissolve.  The chemist that lives at my house said I should have used warm water.  So I will try again.  I did not get the subtle sheen I was hoping for.....could be lack of dissolving properly. 

I am now prepped to try once again!~

Roberta

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bciskepottery    925

That is funny this thread popped up again.  I saw the soda ash wash picture in John Britt's book and thought it would be fun to try.  I got some soda ash from a tie dying friend. I had a heck of a time getting the soda ash to dissolve.  The chemist that lives at my house said I should have used warm water.  So I will try again.  I did not get the subtle sheen I was hoping for.....could be lack of dissolving properly. 

I am now prepped to try once again!~

Roberta

You need hot water to dissolve the soda ash. Only make enough at a time for what you need.

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I keep a half gallon jug of soda ash solution on the shelf in the glaze studio to be used for spraying on raw clay bisque ware or over any cone 10 glaze to give it a shine or some orange to deep red coloration.  I make it up with tap water, powdered SA and shake.  It keeps for ever.  Don't leave it in the spray bottle as it will often plug the spray nozzle and take more time to clean than it does to empty the spray bottle back into the storage jug.  If you use hot water the solution will precipitate crystals when the solution cools and you will get crystals that plug the sprayer. 

 

I also keep TSP and 20-MuleTeam borax solutions available for spray washes.  The shelf life of the solutions are equal to the life of the container , not the contents.

 

LT

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Joseph F    865

I know this is an old thread I am bumping, but I am wondering if anyone has tried sponging or using soda wash on top/underneath a glazed surface and what happens to the glaze itself? 

 

For example taking a sprayer and spraying soda wash on the bisque surface then spraying glazes like normal, would this have any effect on the glaze? I assume it would, but I haven't tried it yet. I am planning on trying it very soon though. If anyone has done this, any tips/tricks?

 

I am not too concerned with element life. If I can get the look I am after I will just replace the elements more.

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neilestrick    1,381

The salts will come to the surface to some degree as the piece dries, and it will flux out the glaze. I suppose there's also the danger of the clay body being fluxed out, which would be a bad thing.

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I soaked a porcelain lidded jar (about three inch diam by three inches tall) in a liter container of soda ash solution until all the liquid evaporated. The jar was covered with white crystals. Dried over summer break. Fired in reduction gas kiln to cone 10 sitting on sea shells . Lid was glazed to bottom, thick clear glaze all over. Some crazing of glaze as expected. No carbon trapping. Looked good. Otherwise a boring pot with stuck lid.

 

For three years I routinely fired all my work with a sprayed coats of one or more of borax, trisodiumphosphate, or soda ash saturated solutions either before,after, or without a dipped coat of one of our studio cone 10 glazes. No disasters. On raw clay the effects were similar to wood firing in color. On porcelain reddish color with a sheen from TSP.

 

LT

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Babs    386

I have asked this question before, and it is only because it is a similar colour which appears on the pots to soda wash, but no sheen...

I've been getting a toasty colour on some of my bisque ware. When tumbled packed the toasty colour can be seen on the parts of the pots with more surface to the atmosphere of the kiln, esp pots at the top of the kiln. toploader.

This is only occurring since I purchased a new kiln .

I had a glaze run onto the kiln floor and a shelf, it contained magnesium, glaze puddle still there, well evidence of it, I didn't feel like digging into my new floor.

AND I have done the soda ash wash on pots.

Any of these actions cause a colouring of my white bisque ware? No photos of this but will look out for it.

I bisque terracotta and the white clay pots in same firing but I have done this for ever.

This kiln is unvented, I leave the bungs out till 700deg.C

It's a piglet of a kiln. with all bungs open, 25 deg. /hr to 100degC and 100/hr to 600, then 150 to end, it still oozes rust coloured stuff onto my verandah floor. verandah is covered , sides as well where the kiln sits.

My ware is dried , well same as for ever, but I am just a couple of Kms. from the ocean.

Any suggestions welcome.

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Joseph F    865

Eh, it doesn't sound like it is worth the results when glazing over it. I will give it a few shots to see but thanks for all the information everyone.

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Babs    386

Joseph, I applied it to the bottom 1/3 of my pot, and glazed to that point. I was careful not to handle the area of soda wash incase I removed some with my fingertips.

I saw no ugly over fluxed areas, the interface of soda and glaze seemed ok, you could put a resist over the soda wash perhaps

I'll try to find a photo.

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Joseph F    865

It's okay babs. Don't worry about it. I have been thinking about what I want and soda sheen isn't it. I appreciate the effort though.

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